Answer:
x = 3
Step-by-step explanation:
The two marked angles form a linear pair, so are supplementary. Their sum is 180°.
(3x +136)° +(5x +20)° = 180°
8x +156 = 180 . . . . . . . . . . . divide by °, collect terms
8x = 24 . . . . . . . . . . . . . . subtract 156
x = 3 . . . . . . . . . . . . . . divide by 8
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Additional comment
We suspect the intended answer for the second question is A 25° and 65°. These are possible measures for the acute angles in a right triangle, which must total 90°. No angle will be more than 90° (eliminates C and D), and the two smallest angles must total 90° (eliminates B).
